Graphene and Silver Nanoparticle-Coated Poly(vinyl) Alcohol/Graphene Oxide/Dioctyl Terephthalate: Bis(2-hydroxyethyl) Terephthalate Composite Strain Sensors

Polymer-based substrates have recently become popular for flexible electronic applications due to their flexibility and durability; however, they still have limited applications in flexible electronic device manufacturing due to poor sensitivity at low strain levels. In this study, graphene nanoplatelets (GNPs) and silver nanoparticles (AgNPs) were spray-coated onto wettable polymer composites formed from poly(vinyl alcohol) (PVA), graphene oxide (GO), dioctyl terephthalate, and bis (2-hydroxyethyl) terephthalate (BHET). The Technique for Order Preference by Similarity to the Ideal-Solution-based Taguchi method was used to analyze the factor effect and determine the optimum strain sensor design. Graphene and AgNPs-coated PVA/GO/BHET polymer composites fabricated using the layer-by-layer spray-coating technique represent the optimum strain sensor for the analyzed samples. It showed gauge factors of 33.89 and 26.51, respectively, under a small compressive and tensile strain range of 0.04% and a sheet resistance of 1.459 ± 0.053 kohm/sq. The high gauge factor and low sheet resistance of the optimum coating were attributed to a synergetic effect of the GNPs and AgNPs, which diffuse inside the graphene network. This work suggests that BHET is a highly promising candidate both as a PET recycling material and for producing sensors due to its ability to form hydrogen bonds.